30 pin connector used on the dock station for iPod and iPhone.
Available in all Apple iPod MP3 player (iPod 1G, 2G, 3G, 4G, 5G and Nano).
iphone接口定义英文版的：
This connector is used on iPod (starting from 3rd generation) and iPhone. It is used to connect the iPod or iPhone to various devices: PC (via USB or FireWire IEEE1394), audio amplifier, serial device (controlled via the Apple Accessory Protocol).
Pin Signal Description
1 GND Ground (-), internaly connected with Pin 2 on iPod motherboard
2 GND Audio and Video ground (-), internaly connected with Pin 2 on iPod motherboard
3 Right Line Out - R (+) (Audio output, right channel)
4 Left Line Out - L(+) (Audio output, left channel)
5 Right In Line In - R (+)
6 Left In Line In - L (+)
8 Video Out Composite video output (only when the slideshow mode is active on iPod Photo)
9 S-Video Chrominance output for iPod Color, Photo only
10 S-Video Luminance output for iPod Color, Photo only
11 GND Serial GND
12 Tx ipod sending line, Serial TxD
13 Rx ipod receiving line, Serial RxD
14 NC
15 GND Ground (-), internaly connected with pin 16 on iPod motherboard
16 GND USB GND (-), internaly connected with pin 15 on iPod motherboard
17 NC
18 3.3V 3.3V Power (+)
Stepped up to provide +5 VDC to USB on iPod Camera Connector.
If iPod is put to sleep while Camera Connector is present, +5 VDC at this pin slowly drains back to 0 VDC.
19,20 +12V Firewire Power 12 VDC (+)
21 Accessory Indicator/Serial enable Different resistances indicate accessory type:
1KOhm - iPod docking station, beeps when connected
10KOhm - Takes some iPods into photo import mode
500KOhm - related to serial communication / used to enable serial communications Used in Dension Ice Link Plus car interface
1MOhm - Belkin auto adaptor, iPod shuts down automatically when power disconnected Connecting pin 21 to ground with a 1MOhm resistor does stop the ipod when power (i.e. Firewire-12V) is cut. Looks to be that when this pin is grounded it closes a switch so that on loss of power the Ipod shuts off. Dock has the same Resistor.
22 TPA (-) FireWire Data TPA (-)
23 5 VDC (+) USB Power 5 VDC (+)
24 TPA (+) FireWire Data TPA (+)
25 Data (-) USB Data (-)
26 TPB (-) FireWire Data TPB (-)
27 Data (+) USB Data (+)
Pins 25 and 27 may be used in different manner. To force the iPod 5G to charge in any case, when 'USB Power 5 VDC' (pin 23) is fed, 25 must be connected to 5V through a 10KOhm resistor, and 27 must be connected to the Ground (for example: pin 1) with a 10KOhm resistor.
28 TPB (+) FireWire Data TPB (+)
29,30 GND FireWire Ground (-)
Notes
Signals with grey background may not exist on some docking stations.
Apple serial devices (i.e. iTalk and remote control) communicate with iPod (3rd generation or more) using the Apple Accessory Protocol.
The serial connection uses a standard 19200 baud 8N1 protocol (the speed can be increased up to 57600 but tends to become unstable).
来个中文的iphone接口定义：
接口排列方式为:
1.2.3.4.5.6.7.8.9...........29.30
内部焊接点排列为:
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
接口定义为:
1 Ground (-) 地 *
2 Line Out - Common Ground (-) 线路输出 地*
3 Line Out - R (+) R声道线路输出
4 Line Out - L (+)L声道线路输出
5 Line In - R (+) R声道线路输入
6 Line In - L (+) L声道线路输入
7
8 Video Out - Composite Video (for ipod colour when slideshow activated) 复合视频输出 (只有彩屏的ipod有效)******
9
10
11 Serial GNDRS-232串口 地
12 Serial TxD RS-232串口 TxD
13 Serial RxD RS-232串口 RxD
14
15 Ground (-) 地 **
16 USB GND (-) USB电源负极 **
17
18 3.3V Power (+) 3.3V电源正极
19 Firewire Power 12 VDC (+) 1394火线12V电源 正极 ***
20 Firewire Power 12 VDC (+)1394火线12V电源 正极***
21 Accessory Indicator 附件识别接口 ****
22 FireWire Data TPA (-) 1394火线数据 TPA(-)
23 USB Power 5 VDC (+)USB 5V 电源 正极
24 FireWire Data TPA (+) 1394火线数据 TPA(+)
25 USB Data (-)USB 数据(-)
26 FireWire Data TPB (-)1394火线数据 TPA(-)
27 USB Data (+) USB 数据(+)
28 FireWire Data TPB (+) 1394火线数据 TPB(+)
29 FireWire Ground (-) 1394火线12V电源 负极*****
30 FireWire Ground (-) 1394火线12V电源 负极*****